WO2016129255A1 - Glass for laser processing, and method for producing glass with hole using said glass for laser processing - Google Patents

Abstract

The present invention provides, in a fine hole batch processing technology that combines etching and the formation of an altered portion by means of UV laser irradiation, a glass composition that makes it possible to produce a hole having a circular outline and a smooth inner wall and enables viable continuous production. The present invention relates to a glass for laser processing, wherein the composition of the glass, expressed by mol%, includes 45.0 % ≤ SiO₂ ≤ 70.0%, 2.0% ≤ B₂O₃ ≤ 20.0%, 3.0% ≤ Al₂O₃ ≤ 20.0%, 0.1% ≤ CuO ≤ 2.0%, 0% ≤ TiO₂ ≤ 15.0%, and 0% ≤ ZnO ≤ 9.0%, wherein 0 ≤ Li₂O+Na₂O+K₂O < 2.0%.

Description

Glass for laser processing and method for producing glass with holes using the same

The present invention relates to a glass for laser processing and a method for producing glass with holes using the same.

A material in which a large number of fine through holes are arranged is used as a microelement used in MEMS or an electronic device. As this material, a silicon wafer that is small in expansion and contraction due to a temperature change and hardly breaks is generally used (CTE = 35 × 10 ⁻⁷ / ° C.). In addition, since the coefficient of thermal expansion (CTE) is small, there is a feature such that the variation in characteristics due to temperature change is small. On the other hand, the production of a silicon single crystal, which is a base material for a silicon wafer, is very expensive, and therefore the silicon wafer is also very expensive. Furthermore, in laser processing using ablation, which is a hole drilling method for silicon wafers that have been put to practical use, it is necessary to irradiate a single hole with multiple pulses, which makes high-speed processing difficult and increases tact time. In addition, the processing cost is high.

On the other hand, there is known a technique (Patent Document 1) that enables a high-speed drilling process of 1000 or more per second by combining ultraviolet laser pulse irradiation and wet etching. According to this processing method, a laser beam having a wavelength of 535 nm or less is condensed by a predetermined lens, and then irradiated to a substrate-like glass where a hole is to be formed, thereby forming an altered portion. Further, by utilizing the fact that the formed altered part has a higher etching rate than other parts, the glass in which the altered part is formed is immersed in a hydrofluoric acid solution, and through-holes or bottoms are formed in the altered part. A hole is formed.

According to the patent document 1, in the titanium-containing silicate glass described in Examples 1 and 12, etc., simultaneous production of cylindrical or frustoconical through holes is realized. However, since the glass compositions disclosed in the examples contain a large amount of alkali metals in the form of oxides, their thermal expansion coefficient is larger than that of silicon wafers, and are not suitable for MEMS and electronic device applications. As a nucleating agent, it contains a high concentration of titanium known as a component that promotes the occurrence of devitrification, so that the glass is easily devitrified and is not suitable for continuous production. There are problems such as contamination.

Japanese Patent No. 4667289

The present invention provides a glass capable of producing a hole having a circular outline and a smooth inner wall, and capable of practical continuous production, in a micro-hole batch processing technique combining an altered portion formation by ultraviolet laser irradiation and etching. The purpose is to do.

The present inventors have found for the first time that good pore quality can be obtained by using Cu ions in combination even when the glass cannot contain sufficient pore quality simply by containing Al.

In the present invention, the glass composition is expressed in mol%,
45.0% ≦ SiO ₂ ≦ 70.0%,
2.0% ≦ B ₂ O ₃ ≦ 20.0%,
3.0% ≦ Al ₂ O ₃ ≦ 20.0%,
0.1% ≦ CuO ≦ 2.0%,
0% ≦ TiO ₂ ≦ 15.0%, and 0% ≦ ZnO ≦ 9.0%,
And 0 ≦ Li ₂ O + Na ₂ O + K ₂ O <2.0%
A glass for laser processing is provided.

Further, the present invention uses a step [i] of forming an altered portion in the irradiated portion by condensing a predetermined laser pulse with a lens and irradiating the laser processing glass with the etching solution. Thus, a method for producing glass with holes is provided by the step [ii] of etching at least the altered portion.

By using the laser processing glass of the present invention, a glass having a hole having a circular contour and a smooth inner wall can be produced in a microhole batch processing technique combining the formation of an altered portion by ultraviolet laser irradiation and etching. it can. Moreover, the glass which concerns on this invention can suppress the deformation | transformation of glass, such as a crack around a process part, by a predetermined | prescribed perforation method, and can obtain glass provided with a hole with few dispersion | variations in a surface. Furthermore, since the laser used in the present invention generates a harmonic of the Nd: YVO laser and can use a nanosecond laser, it is not necessary to use an expensive femtosecond laser and is industrially advantageous. . Furthermore, the glass of the present invention can be used as a non-alkali glass substrate as a component for display devices such as a display or a touch panel when it satisfies optical characteristics such as transmittance characteristics even if it does not reach processing such as perforation. It does not prevent application.

It is a schematic diagram of the manufacturing method of this invention. It is explanatory drawing regarding the circularity or outline evaluation method of this invention. It is explanatory drawing regarding the evaluation method of the smoothness of the hole inner wall of this invention. It is explanatory drawing regarding the evaluation method of the depth of the hole of the glass of this invention. It is explanatory drawing regarding the application example (glass substrate for interposers) using the glass for laser processing of this invention.

In the glass for laser processing of the present invention, the glass composition is expressed in mol%,
45.0% ≦ SiO ₂ ≦ 70.0%,
2.0% ≦ B ₂ O ₃ ≦ 20.0%,
3.0% ≦ Al ₂ O ₃ ≦ 20.0%,
0.1% ≦ CuO ≦ 2.0%,
0% ≦ TiO ₂ ≦ 15.0%, and 0% ≦ ZnO ≦ 9.0%,
And 0 ≦ Li ₂ O + Na ₂ O + K ₂ O <2.0%
It is characterized by being.

The average thermal expansion coefficient (in the present specification, simply referred to as “thermal expansion coefficient”) of the glass for laser processing according to the present invention is preferably 70 × 10 ⁻⁷ / ° C. or less, and preferably 60 × 10 more preferably ^-7 / ° C. or less, still more preferably 50 × 10 ^-7 / ℃ less, particularly preferably 45 × 10 ^-7 / ℃ or less. Further, the lower limit of the thermal expansion coefficient is not particularly limited, but may be, for example, 10 × 10 ⁻⁷ / ° C. or higher, or 20 × 10 ⁻⁷ / ° C. or higher. The thermal expansion coefficient is measured as follows. First, a cylindrical glass sample having a diameter of 5 mm and a height of 18 mm is prepared. This is heated from 25 ° C. to the yield point of the glass sample, and the thermal expansion coefficient is calculated by measuring the elongation of the glass sample at each temperature. An average value of thermal expansion coefficients in the range of 50 to 350 ° C. can be calculated to obtain an average thermal expansion coefficient. The actual coefficient of thermal expansion was measured using a thermomechanical analyzer TMA4000SA manufactured by NETZSCH at a temperature increase rate of 5 ° C./min.

For the glass according to the present invention, the absorption coefficient α in the wavelength range of the laser to be irradiated is important. The absorption coefficient α of the laser processing glass of the present invention is preferably 1 to 50 / cm, more preferably 2 to 40 / cm, still more preferably 2 to 35 / cm at the dominant wavelength of the laser beam to be irradiated. You may adjust to the absorption coefficient required in order to form an alteration part in the full width direction. When the absorption coefficient α is too small, the laser beam passes through the glass and the glass cannot absorb the energy of the laser, and the altered portion cannot be formed. On the other hand, if it is too large, the energy of the laser is absorbed near the glass surface, and the altered part cannot be formed deep in the thickness direction of the glass with a single laser pulse, resulting in the formation of holes. It will not be easy.

The absorption coefficient α can be calculated by measuring the transmittance and reflectance of a glass substrate having a thickness t (cm). For a glass substrate having a thickness t (cm), a transmittance T (%) at a predetermined wavelength (wavelength 535 nm or less) and a reflectance R (%) at an incident angle of 12 ° are measured with a spectrophotometer (for example, JASCO Corporation). Measured using an ultraviolet-visible near-red spectrophotometer V-670). The absorption coefficient α is calculated from the obtained measured value using the following formula.
α = (1 / t) * ln {(1-R) / T}

Each component that can be included in the laser processing glass of the present invention will be described below. In the present specification, the upper limit value and the lower limit value of the numerical ranges (content of each component, values calculated from each component, physical properties, etc.) can be appropriately combined. In the present invention, “substantially does not contain” a certain component means that the content of the component in the glass is less than 0.1 mol%, preferably less than 0.05 mol%, more preferably 0.01. It means less than mol%.

(1) SiO ₂
SiO ₂ is a network-forming oxide that constitutes the main network of glass. By including SiO ₂ , the chemical durability can be improved, the relationship between temperature and viscosity can be adjusted, and the devitrification temperature can be adjusted. When the content of SiO ₂ is too large, it becomes difficult to melt at a practical temperature of less than 1700 ° C., and when the content of SiO ₂ is too small, the liquidus temperature at which devitrification occurs is lowered. In the glass of the present invention, the content of SiO ₂ is 45.0 mol% or more, preferably 50.0 mol% or more, more preferably 52.0 mol% or more, and further preferably 55.0 mol% or more. . The content of SiO ₂ is 70.0 mol% or less, preferably 68.0 mol% or less, more preferably 67.0 mol% or less, and further preferably 66.0 mol% or less.

(2) B ₂ O ₃
B ₂ O ₃ is a network-forming oxide that constitutes the main network of glass, like SiO ₂ . By including B ₂ O ₃ , the liquidus temperature of the glass can be lowered and adjusted to a practical melting temperature. In an alkali-free or slightly alkali glass having a relatively high SiO ₂ content, it is difficult to melt at a practical temperature of less than 1700 ° C. when the content of B ₂ O ₃ is too small. Even when the content of B ₂ O ₃ is too large, the volatilization amount increases at high temperature melting, and it becomes difficult to maintain the composition ratio stably. The content of B ₂ O ₃ is 2.0 to 20.0 mol%. Further, if it is less than 6.0 mol%, the viscosity increases and the difficulty of melting the glass increases, and if it exceeds 18.0 mol%, the strain point decreases, so the content of B ₂ O ₃ Is preferably 6.0 mol% or more, more preferably 6.5 mol% or more, and even more preferably 7.0 mol% or more. The content of B ₂ O ₃ is preferably 18.0 mol% or less, more preferably 17.0 mol% or less, and further preferably 16.5 mol% or less.

(3) SiO ₂ + B ₂ O ₃
Regarding the sum of these network forming components (SiO ₂ + B ₂ O ₃ ), if it exceeds 80.0 mol%, it becomes extremely difficult to melt the glass. Therefore, the sum of these network forming components is 80.0 mol% or less. Is preferable, 78.0 mol% or less is more preferable, 76.0 mol% or less is more preferable, and 74.0 mol% or less is particularly preferable. The sum of these network forming components is preferably 55.0 mol% or more, more preferably 58.0 mol% or more, further preferably 59.0 mol% or more, and particularly preferably 62.0 mol% or more.

(4) Al ₂ O ₃
The present invention is characterized in that it has a moderately weak bond strength capable of forming an altered portion by laser irradiation energy, although it is not necessary to directly cut the bond by laser ablation, that is, completely cut the bond. .

Al ₂ O ₃ is a so-called intermediate oxide, depending on the balance between the above-described network-forming components SiO ₂ and B ₂ O ₃ and the content of an alkaline earth metal oxide, which will be described later, which is a modified oxide. Alternatively, it can function as the latter oxide. On the other hand, Al ₂ O ₃ is a component that takes 4-coordination, stabilizes glass, prevents phase separation of borosilicate glass, and increases chemical durability. In an alkali-free or slightly alkaline glass having a relatively large SiO ₂ content, it is difficult to melt at a practical temperature of less than 1700 ° C. when the content of Al ₂ O ₃ is too small. Even when the content of Al ₂ O ₃ is too large, the melting temperature of the glass rises and it becomes difficult to stably form the glass. The content of Al ₂ O ₃ is 3.0 to 20.0 mol%. Further, if it is less than 6.0 mol%, the strain point may be lowered, and if it exceeds 18.0 mol%, the surface tends to become cloudy. Therefore, it is preferably 6.0 mol% or more, and 6.5 mol%. The above is more preferable, 7.0 mol% or more is further preferable, and 7.5 mol% or more is particularly preferable. The content of Al ₂ O ₃ is preferably 18.0 mol% or less, more preferably 17.5 mol% or less, further preferably 16.0 mol% or less, and particularly preferably 13.5 mol% or less. .

(5) TiO ₂
TiO ₂ is a so-called intermediate oxide and is generally used for adjusting the melting temperature and devitrification. Also in the glass processing method by laser ablation, it is known that the processing threshold by laser can be lowered by containing TiO ₂ in glass to be processed (Japanese Patent No. 4495675). In patent No. 4495675, in a glass composition that can be processed relatively easily without cracking in laser processing, it is composed of a network modification oxide (alkali metal oxide, alkaline earth metal oxide, transition metal oxide, etc.), For example, weak bonds such as Na—O bonds do not contribute to laser processability, and the laser processability is determined by the bond strength of network-forming oxides and intermediate oxides excluding weak bonds due to network-modified oxides such as Na—O. It is supposed to be characterized. In this case, it is understood that a sufficient amount of intermediate oxide has been introduced into the glass composition to completely break the bond by the energy of the irradiated laser. According to the classification of glass forming ability by single bond strength according to Kuan-Han Sun (J. Amer. Ceram. Soc. Vol. 30, Sep 1947, pp 277-281), TiO ₂ has an intermediate bond strength. It belongs to oxides. In the method of manufacturing a glass with a hole that uses both laser irradiation and etching, the energy of a relatively weak laser or the like can be obtained by including TiO ₂ in a non-alkali glass or a fine alkali glass having a specific composition such as containing CuO. Irradiation makes it possible to form an altered portion, and the altered portion can be easily removed by subsequent etching. In short, TiO ₂ can be expected to have an effect of adjusting the laser processability of glass.

It is also well known that by containing an appropriate amount of TiO ₂ in glass, the effect of coloring colored components such as Fe and Cu contained simultaneously is affected. That is, it can be said that it also has a function of adjusting the absorption coefficient α in the wavelength region of a predetermined laser. Therefore, in the present invention, for the purpose of facilitating the formation of the altered portion in which the hole is formed by the etching process of the manufacturing method using both laser irradiation and etching, so that the glass has an appropriate absorption coefficient α, TiO ₂ may be contained. On the other hand, if the content of TiO ₂ is too large, chemical resistance, particularly hydrofluoric acid resistance, is excessively increased, and in some cases, such as holes are not properly formed in the etching process after laser irradiation. Therefore, the glass of the present invention may contain substantially no TiO ₂ . In addition, the excessive concentration of TiO ₂ may increase the coloring density and may not be suitable for molding glass for display applications. In the glass of the present invention, the content of TiO ₂ is 0 to 15.0 mol%, and 0 to 10.0 mol% is preferable from the viewpoint of excellent smoothness of the inner wall surface of the hole obtained by laser irradiation. It is more preferably 0.0 to 10.0 mol%, further preferably 1.0 to 9.0 mol%, and particularly preferably 1.0 to 5.0 mol%.

Glass of the present invention, (excluding the content of TiO ₂ is 0 mol%) containing TiO ₂ case, the content of TiO ₂ content (molar%) CuO divided by the (mol%) ( " “TiO ₂ / CuO”) depends on the combination with other components, but is preferably 1.0 or more, and more preferably 1.5 or more from the viewpoint of excellent smoothness of the inner wall surface of the hole obtained by laser irradiation. More preferred is 2.0 or more. TiO ₂ / CuO is preferably 20.0 or less, more preferably 15.0 or less, and even more preferably 12.0 or less.

(6) ZnO
ZnO is used for adjusting the melting temperature and devitrification. ZnO is a component that may have a single bond strength comparable to that of an intermediate oxide depending on the composition. When there is too much content of ZnO, it will become easy to devitrify glass. Therefore, the glass of the present invention contains substantially no ZnO (ZnO content is less than 0.1 mol%, preferably less than 0.05 mol%, more preferably 0.01 mol% or less. May be used. In view of such characteristics, in the glass of the present invention, the content of ZnO is 0 to 10.0 mol%, preferably 1.0 to 10.0 mol%, preferably 1.0 to 9.0 mol%. % Is more preferable, and 1.0 to 7.0 mol% is more preferable.

(7) MgO
Among the alkaline earth metal oxides, MgO has the characteristics that it suppresses an increase in the thermal expansion coefficient and does not excessively lower the strain point, and may be included to improve the solubility. However, if the content of MgO is too large, the glass is not preferable because it causes phase separation, devitrification characteristics, and acid resistance. In the glass of the present invention, the content of MgO is preferably 15.0 mol% or less, more preferably 12.0 mol% or less, still more preferably 10.0 mol% or less, and particularly preferably 8.5 mol% or less. The MgO content is preferably 2.0 mol% or more, more preferably 2.5 mol% or more, further preferably 3.0 mol% or more, and particularly preferably 3.5 mol% or more.

(8) CaO
CaO, like MgO, has the characteristics of suppressing an increase in the thermal expansion coefficient and not excessively reducing the strain point, and may be included to improve the solubility. However, if the content of CaO is too large, the devitrification characteristics are deteriorated, the thermal expansion coefficient is increased, and the acid resistance is lowered. In the glass of the present invention, the content of CaO is preferably 15.0 mol% or less, more preferably 10.0 mol% or less, further preferably 6.5 mol% or less, and particularly preferably 6.0 mol% or less. Further, the CaO content is preferably 1.0 mol% or more, more preferably 1.5 mol% or more, further preferably 2.0 mol% or more, and particularly preferably 2.5 mol% or more.

(9) SrO
SrO, like MgO and CaO, has the characteristics that it suppresses the increase in the thermal expansion coefficient and does not excessively lower the strain point, and also improves the solubility, thus improving the devitrification characteristics and acid resistance. For this purpose, it may be contained. However, too much SrO is not preferable because it causes deterioration of devitrification characteristics, an increase in thermal expansion coefficient, and a decrease in acid resistance and durability. In the glass of the present invention, the content of SrO is preferably 15.0 mol% or less, more preferably 10.0 mol% or less, further preferably 6.5 mol% or less, and particularly preferably 6.0 mol% or less. The SrO content is preferably 1.0 mol% or more, more preferably 1.5 mol% or more, further preferably 2.0 mol% or more, and particularly preferably 2.5 mol% or more.

(10) BaO
BaO may be contained in an appropriate amount because it is effective in adjusting the etching property, improving the phase separation and devitrification properties of the glass, and improving the chemical durability. In the glass of the present invention, the BaO content is preferably 15.0 mol% or less, more preferably 12.0 mol% or less, further preferably 10.0 mol% or less, and particularly preferably 6.0 mol% or less. Further, the BaO content is preferably 1.0 mol% or more, more preferably 2.0 mol% or more, further preferably 3.0 mol% or more, and particularly preferably 3.5 mol% or more. However, in consideration of other alkaline earth metal oxides, it may not be substantially contained.

(11) MgO + CaO + SrO + BaO
Alkaline earth metal oxides (MgO, CaO, SrO, and BaO) have the above-described effects, and are components that adjust the melting temperature of glass while generally suppressing an increase in thermal expansion coefficient. Used to adjust viscosity, melting temperature and devitrification. However, if the content of the alkaline earth metal oxide is too large, the glass tends to be devitrified. Therefore, in the glass of the present invention, the total content of these alkaline earth metal oxides (hereinafter referred to as “ΣRO”). 25.0 mol% or less is preferable, 23.0 mol% or less is more preferable, 20.0 mol% or less is more preferable, and 18.0 mol% or less is particularly preferable. ΣRO is preferably 6.0 mol% or more, more preferably 8.0 mol% or more, further preferably 10.0 mol% or more, and particularly preferably 10.5 mol% or more.

(12) Li ₂ O, Na ₂ O, K ₂ O
Alkali metal oxides (Li ₂ O, Na ₂ O, and K ₂ O) are components that can greatly change the properties of glass. Since the solubility of the glass is remarkably improved, it may be contained. However, since the influence on the increase of the thermal expansion coefficient is particularly great, it is necessary to adjust according to the use. In particular, in glass used in the electronics field, it diffuses into nearby semiconductors during the subsequent heat treatment, significantly reduces electrical insulation, increases dielectric constant (ε) or dielectric loss tangent (tan δ), and increases high frequency There is a risk of deteriorating characteristics. If these alkali metal oxides are contained in the glass, the glass surface is coated with another dielectric material after the glass is molded, so that at least the diffusion of alkali components to the surface can be prevented. The point can be solved. The coating method is effective by a known technique such as a physical method such as sputtering or vapor deposition of a dielectric such as SiO ₂ or a film formation method from a liquid phase by a sol-gel method. On the other hand, the glass of the present invention may be a non-alkali (Li ₂ O + Na ₂ O + K ₂ O = 0 mol%) glass that does not contain an alkali metal oxide, and is a fine alkali glass that allows some alkali components. May be. The content of the alkali metal oxide contained in the fine alkali glass is preferably less than 2.0 mol%, may be less than 1.0 mol%, and more preferably less than 0.1 mol%. , More preferably less than 0.05 mol%, particularly preferably less than 0.01 mol%. The content of the alkali metal oxide contained in the fine alkali glass may be 0.0001 mol% or more, 0.0005 mol% or more, or 0.001 mol% or more. Also good.

(13) CuO
CuO is an essential component in the present invention. When CuO is contained, the glass is colored, and the absorption coefficient α at a predetermined laser wavelength is appropriately set to appropriately absorb the energy of the irradiation laser. It is possible to easily form an altered portion that is the basis for hole formation.

The content of CuO is preferably 2.0 mol% or less, more preferably 1.9 mol% or less, still more preferably 1.8 mol% or less, so that it falls within the numerical range of the absorption coefficient α described above. 6 mol% or less is particularly preferable. The content of CuO is preferably 0.1 mol% or more, more preferably 0.15 mol% or more, further preferably 0.18 mol% or more, and particularly preferably 0.2 mol% or more.

In the present invention, the value obtained by dividing the content (mol%) of Al ₂ O _{3 by} the content (mol%) of CuO (“Al ₂ O ₃ / CuO”) depends on the combination with other components. From the viewpoint of excellent smoothness of the inner wall surface of the hole obtained by laser irradiation, it is preferably 4.0 or more, more preferably 5.0 or more, still more preferably 6.0 or more, and particularly preferably 6.5 or more. . Further, Al ₂ O ₃ / CuO is preferably 120.0 or less, more preferably 80.0 or less, further preferably 60.0 or less, and particularly preferably 56.0 or less.

(13) Other coloring component In the present invention, the “other coloring component” means a metal oxide having a large coloring effect when contained in a glass other than CuO and TiO ₂ . Specifically, it is a metal oxide selected from the group consisting of Fe, Ce, Bi, W, Mo, Co, Mn, Cr, and V, and contains one or more (two or more) types. May be. This contributes to the function of absorbing the energy of ultraviolet laser light directly or indirectly in order to contribute to the formation of the altered portion of the glass.

(14) Other components As a glass production method, a float method, a roll-out method, a fusion method, a slot-down method, a casting method, a pressing method, and the like can be used. Since it can be obtained, the fusion method is suitable for producing glass for substrates used in the field of electronic technology. When melting and molding glass by a fusion method or the like, a clarifying agent may be added.

(14-1) Clarifier The clarifier is not particularly limited, but oxides such as As, Sb, Sn and Ce; sulfides such as Ba and Ca; chlorides such as Na and K; F, F ₂ , Examples thereof include Cl, Cl ₂ and SO ₃ . The glass of the present invention is a group consisting of oxides such as As, Sb, Sn, and Ce, sulfides such as Ba and Ca, chlorides such as Na and K, F, F ₂ , Cl, Cl ₂ , and SO _3. 0 to 3.0 mol% of at least one refining agent selected from the following can be contained (excluding 0 mol%). Fe ₂ O ₃ can also function as a fining agent, but in the present specification, Fe ₂ O ₃ means a coloring component.

(14-2) Impurities from the glass manufacturing facility Impurities from the glass manufacturing facility may be mixed when the glass is manufactured. The glass of this invention is not specifically limited as long as the effect of this invention is acquired, The glass containing such an impurity is also included. Impurities arising from glass production equipment include Zr and Pt (both are refractory materials for glass production equipment (melting, forming processes, etc.) or main materials for electrodes, and Zr may be used as the main material for refractory materials as ZrO _2. And the like. Due to this, the glass of the present invention may contain a slight amount (for example, 3.0 mol% or less) of at least one selected from the group consisting of ZrO ₂ and Pt. Although ZrO ₂ as previously described may be included in the glass as intermediate oxide, even if not contained in the positively glass ZrO _2, as an impurity from the glass manufacturing facility as described above, slightly An amount of Zr component may be included in the glass.

(14-3) Moisture The molded glass may contain some moisture. There is a β-OH value as an index for defining the water content. beta-OH value, and the transmittance T ₁ in the reference wavenumber 3846cm ^-1 of a glass substrate having a thickness of t '(mm) (%) , the minimum transmittance T ₂ in the vicinity of the hydroxyl group absorption wave 3600 cm ^-1 a (%) FT It is calculated by the equation (1 / t ′) × log (T ₁ / T ₂ ) by measuring by the IR method. The β-OH value may be about 0.01 to 0.5 / mm, and decreasing this value contributes to increasing the strain point, but conversely if too small, the solubility tends to decrease.

As a preferred embodiment (X-1) of the present invention, for example, the glass composition is
Displayed in mol%
45.0% ≦ SiO ₂ ≦ 68.0%,
2.0% ≦ B ₂ O ₃ ≦ 20.0%,
3.0% ≦ Al ₂ O ₃ ≦ 20.0%, and 0.1% ≦ CuO ≦ 2.0%,
Substantially free of TiO ₂ and ZnO and 58.0% ≦ SiO ₂ + B ₂ O ₃ ≦ 80.0%,
8.0% ≦ MgO + CaO + SrO + BaO ≦ 20.0%,
0 ≦ Li ₂ O + Na ₂ O + K ₂ O <2.0%,
6.0 ≦ Al ₂ O ₃ /CuO≦60.0
Aluminoborosilicate glass.

As another preferred embodiment (X-2) of the present invention, for example, the glass composition is
Displayed in mol%
50.0% ≦ SiO ₂ ≦ 68.0%,
6.0% ≦ B ₂ O ₃ ≦ 18.0%,
7.0% ≦ Al ₂ O ₃ ≦ 18.0%,
0.1% ≦ CuO ≦ 1.8% and 1.0% ≦ TiO ₂ ≦ 10.0%,
Substantially free of ZnO and 58.0% ≦ SiO ₂ + B ₂ O ₃ ≦ 80.0%,
8.0% ≦ MgO + CaO + SrO + BaO ≦ 20.0%,
0 ≦ Li ₂ O + Na ₂ O + K ₂ O <2.0%,
6.0 ≦ Al ₂ O ₃ /CuO≦60.0,
0 ≦ TiO ₂ /CuO≦20.0
Aluminoborosilicate glass.

As another preferred embodiment (X-3) of the present invention, for example, the glass composition is
Displayed in mol%
50.0% ≦ SiO ₂ ≦ 68.0%,
6.0% ≦ B ₂ O ₃ ≦ 18.0%,
7.0% ≦ Al ₂ O ₃ ≦ 18.0%,
0.1% ≦ CuO ≦ 1.8%, and 1.0% ≦ ZnO ≦ 9.0%,
Substantially free of TiO ₂ and 58.0% ≦ SiO ₂ + B ₂ O ₃ ≦ 80.0%,
8.0% ≦ MgO + CaO + SrO + BaO ≦ 20.0%,
0 ≦ Li ₂ O + Na ₂ O + K ₂ O <2.0%,
6.0 ≦ Al ₂ O ₃ /CuO≦60.0
Aluminoborosilicate glass.

In the embodiment (X-1), the composition of the glass is further expressed in mol%,
2.0% ≦ MgO ≦ 10.0%,
1.0% ≦ CaO ≦ 10.0%,
An aluminoborosilicate glass (X-4) containing 1.0% ≦ SrO ≦ 10.0% and 0% ≦ BaO ≦ 6.0% may be used. Similarly, in the embodiments (X-2) and (X-3), the aluminoborosilicate glass (X-5) in which the respective compounding amounts of MgO, CaO, SrO and BaO are the same as (X-4) And (X-6).

In the embodiment (X-1), the composition of the glass is further expressed in mol%,
3.0% ≦ MgO ≦ 8.5%,
2.0% ≦ CaO ≦ 6.5%,
It may be an aluminoborosilicate glass (X-7) containing 2.0% ≦ SrO ≦ 6.5% and 0% ≦ BaO ≦ 6.0%. Similarly, in the embodiments (X-2) and (X-3), the aluminoborosilicate glass (X-8) in which the respective compounding amounts of MgO, CaO, SrO and BaO are the same as (X-7) And (X-9).

In any of the above-described embodiments, the amount of each component can be changed as appropriate based on the above description, and additions, deletions, and the like can be changed for any component. In any of the above embodiments, the composition of each glass and the value of each characteristic (thermal expansion coefficient, absorption coefficient α, etc.) can be appropriately changed and combined. For example, in the glasses of the embodiments (X-1) to (X-9), the thermal expansion coefficient may be 60 × 10 ⁻⁷ / ° C. or less. Further, in the glasses of the embodiments (X-1) to (X-9), the absorption coefficient α may be 2 to 40 / cm.

As another embodiment of the present invention, there is a method for producing glass with holes using the above glass for laser processing. Hereinafter, the manufacturing method will be described.

The manufacturing method of the glass with holes includes the step [i] of forming the altered portion in the irradiated portion by condensing and irradiating the laser processing glass of any of the present invention with a laser pulse with a lens, and etching. And [ii] forming a hole in the laser processing glass by etching at least the altered portion using a liquid.

The glass for laser processing used in the step [i] for forming the altered portion can be produced, for example, as follows.

[Glass melting and molding]
A predetermined amount of glass raw material powder is prepared so that about 300 g of glass can be obtained, and a glass block having a certain volume is prepared by a normal melting and quenching method using a platinum crucible. In the middle, the glass may be stirred for the purpose of improving the glass uniformity or clarifying.

The melting temperature and time can be set to suit the melting characteristics of each glass. The melting temperature may be, for example, about 800 to 1800 ° C., or about 1000 to 1700 ° C. The melting time may be, for example, about 0.1 to 24 hours. In order to relieve the residual stress inside the glass, it is preferable to let it pass through a predetermined temperature range (for example, about 400 to 600 ° C.) over several hours and then naturally cool to room temperature.

By molding in this way, a thin plate-like glass substrate for laser processing having a thickness of about 0.1 to 1.5 mm can be obtained.

[Formation of altered part]
In step [i], the laser processing glass according to any one of the above-described embodiments of the present invention is irradiated with a laser pulse collected by a lens to form an altered portion in the irradiated portion.

In step [i], it is possible to form an altered portion by one pulse irradiation. That is, in the step [i], the altered portion can be formed by irradiating the laser pulse so that the irradiation positions do not overlap. However, the laser pulses may be irradiated so that the irradiation pulses overlap.

In step [i], the laser pulse is usually focused with a lens so that it is focused inside the glass. For example, when forming a through-hole in a glass plate, the laser pulse is usually focused so as to be focused near the center in the thickness direction of the glass plate. When only the upper surface side (laser pulse incident side) of the glass plate is processed, the laser pulse is usually focused so as to be focused on the upper surface side of the glass plate. Conversely, when processing only the lower surface side of the glass plate (the side opposite to the laser pulse incident side), the laser pulse is usually focused so as to be focused on the lower surface side of the glass plate. However, the laser pulse may be focused on the outside of the glass as long as the altered glass portion can be formed. For example, the laser pulse may be focused at a position away from the glass by a predetermined distance (for example, 1.0 mm) from the upper surface or the lower surface of the glass plate. In other words, as long as an altered portion can be formed in the glass, the laser pulse is located within 1.0 mm from the upper surface of the glass in the front direction (the direction opposite to the traveling direction of the laser pulse) (including the upper surface of the glass). Alternatively, focusing may be performed on a position within 1.0 mm (including the position of the lower surface of the glass) or inside the rear surface (the direction in which the laser pulse transmitted through the glass travels) from the lower surface of the glass.

The pulse width of the laser pulse is preferably 1 to 200 ns (nanoseconds), more preferably 1 to 100 ns, and even more preferably 5 to 50 ns. In addition, when the pulse width is larger than 200 ns, the peak value of the laser pulse is lowered, and processing may not be performed well. The laser processing glass is irradiated with a laser beam having an energy of 5 to 100 μJ / pulse. By increasing the energy of the laser pulse, it is possible to increase the length of the altered portion in proportion to it. The beam quality M ² value of the laser pulse may be 2 or less, for example. By using a laser pulse having an M ² value of 2 or less, formation of minute pores or minute grooves is facilitated.

In the manufacturing method of the present invention, the laser pulse may be a harmonic of an Nd: YAG laser, a harmonic of an Nd: YVO ₄ laser, or a harmonic of an Nd: YLF laser. The harmonic is, for example, a second harmonic, a third harmonic, or a fourth harmonic. The wavelength of the second harmonic of these lasers is around 532 nm to 535 nm. The wavelength of the third harmonic is in the vicinity of 355 nm to 357 nm. The wavelength of the fourth harmonic is in the vicinity of 266 nm to 268 nm. By using these lasers, glass can be processed at low cost.

As an apparatus used for laser processing, for example, a high repetition solid-state pulse UV laser: AVIA355-4500 manufactured by Coherent Co., Ltd. may be mentioned. This apparatus is a third harmonic Nd: YVO ₄ laser, and a maximum laser power of about 6 W can be obtained when the repetition frequency is 25 kHz. The wavelength of the third harmonic is 350 nm to 360 nm.

The wavelength of the laser pulse is preferably 535 nm or less, and may be in the range of 350 nm to 360 nm, for example. On the other hand, when the wavelength of the laser pulse is larger than 535 nm, the irradiation spot becomes large and it becomes difficult to produce a microhole, and the periphery of the irradiation spot is easily cracked due to the influence of heat.

As a typical optical system, the oscillated laser is expanded 2 to 4 times with a beam expander (φ7.0 to 14.0 mm at this time), and the center part of the laser is cut off with a variable iris, and then a galvano mirror The optical axis is adjusted, and the light is condensed on the glass while adjusting the focal position with an fθ lens of about 100 mm.

The focal length L (mm) of the lens is, for example, in the range of 50 to 500 mm, and may be selected from the range of 100 to 200 mm.

The beam diameter D (mm) of the laser pulse is, for example, in the range of 1 to 40 mm, and may be selected from the range of 3 to 20 mm. Here, the beam diameter D is a beam diameter of a laser pulse when entering the lens, and means a diameter in a range where the intensity is [1 / e ² ] times the intensity at the center of the beam.

In the present invention, the value obtained by dividing the focal length L by the beam diameter D, that is, the value of [L / D] is 7 or more, preferably 7 or more and 40 or less, and may be 10 or more and 20 or less. This value is related to the light condensing property of the laser irradiated on the glass. The smaller this value is, the more the laser is focused locally, and the more difficult it is to produce a uniform and long altered portion. . If this value is less than 7, the laser power becomes too strong in the vicinity of the beam waist, causing a problem that cracks are likely to occur inside the glass.

In the present invention, it is not necessary to perform a pretreatment (for example, forming a film that promotes absorption of the laser pulse) on the glass before the laser pulse irradiation. However, such a process may be performed as long as the effect of the present invention is obtained.

The numerical aperture (NA) may be varied from 0.020 to 0.075 by changing the laser diameter by changing the size of the iris. If the NA is too large, the laser energy is concentrated only in the vicinity of the focal point, and the altered portion is not formed effectively over the thickness direction of the glass.

By irradiating a pulse laser with a small NA, a deteriorated portion that is relatively long in the thickness direction is formed by one pulse irradiation, which is effective in improving the tact time.

The repetition frequency is preferably 10 to 25 kHz, and the sample is preferably irradiated with laser. Further, by changing the focal position in the thickness direction of the glass, the position (upper surface side or lower surface side) of the altered portion formed in the glass can be optimally adjusted.

Furthermore, the laser output and the operation of the galvanometer mirror can be controlled by the control from the control PC, and the laser is irradiated onto the glass substrate at a predetermined speed based on the two-dimensional drawing data created by CAD software or the like. Can do.

In the portion irradiated with the laser, an altered portion different from other portions of the glass is formed. This altered portion can be easily identified with an optical microscope or the like. Although there is a difference for each glass depending on the composition, the altered portion is generally formed in a cylindrical shape. The altered portion reaches from the vicinity of the upper surface of the glass to the vicinity of the lower surface.

This altered part is a sparse glass in a high temperature region where a photochemical reaction has occurred due to laser irradiation and a defect such as E ′ center or non-bridging oxygen has occurred or due to rapid heating or rapid cooling due to laser irradiation. It is considered that the site retained the structure. Since the altered portion has a higher etching speed with respect to a predetermined etching solution than other portions of the glass, minute holes and grooves can be formed by immersing in the etching solution.

In a conventional processing method using a femtosecond laser device (which is generally expensive), an altered portion is formed while scanning the laser in the depth direction (thickness direction of the glass substrate) so that the irradiation pulses overlap. However, in the hole making technique (a method for producing glass with holes) using both laser irradiation and wet etching according to the present invention, the altered portion can be formed by one laser pulse irradiation.

The conditions selected in step [i] are, for example, that the glass absorption coefficient α is 1 to 20 / cm, the laser pulse width is 1 to 100 ns, and the energy of the laser pulse is 5 to 100 μJ / pulse. And a combination in which the wavelength is 350 nm to 360 nm, the beam diameter D of the laser pulse is 3 to 20 mm, and the focal length L of the lens is 100 to 200 mm.

Before performing the step [ii], the glass plate may be polished as necessary in order to reduce the variation in the diameter of the altered portion. If the polishing is excessively performed, the effect of etching on the altered portion is weakened. Therefore, the polishing depth is preferably 1 to 20 μm from the upper surface of the glass plate.

The size of the altered portion formed in step [i] varies depending on the laser beam diameter D when entering the lens, the focal length L of the lens, the glass absorption coefficient α, the power of the laser pulse, and the like. The obtained altered portion has, for example, a diameter of about 5 to 200 μm and may be about 10 to 150 μm. Further, the depth of the altered portion varies depending on the laser irradiation conditions, the glass absorption coefficient α, and the glass plate thickness, but may be about 50 to 300 μm, for example.

[etching]
In step [ii], holes are formed in the laser processing glass by etching at least the altered portion using an etching solution.

The etchant in the step [ii] preferably has a higher etching rate for the altered portion than the etching rate for the laser processing glass. As the etchant, for example, hydrofluoric acid (aqueous solution of hydrogen fluoride (HF)) may be used. Alternatively, sulfuric acid (H ₂ SO ₄ ) or an aqueous solution thereof, nitric acid (HNO ₃ ) or an aqueous solution thereof, or hydrochloric acid (an aqueous solution of hydrogen chloride (HCl)) may be used. These may be used alone or as a mixture of two or more acids. When hydrofluoric acid is used, etching of the altered portion is easy to proceed, and holes can be formed in a short time. When sulfuric acid is used, the glass other than the altered portion is difficult to be etched, and a straight hole having a small taper angle can be produced.

In the etching process, in order to enable etching from only one side, a surface protective film agent may be applied and protected on the upper surface side or the lower surface side of the glass plate. As such a surface protective film agent, a commercially available product can be used, and examples thereof include silicate-II (manufactured by Trylaner International).

Etching time or etching solution temperature is selected according to the shape of the altered portion or the target processing shape. Note that the etching rate can be increased by increasing the temperature of the etching solution during etching. In addition, the diameter of the hole can be controlled by the etching conditions.

Etching time is not particularly limited because it depends on the plate thickness, but it is preferably about 30 to 180 minutes. The temperature of the etching solution can be changed for adjusting the etching rate, and is preferably about 5 to 45 ° C., more preferably about 15 to 40 ° C.

Although processing is possible even at a temperature of 45 ° C. or higher, it is not practical due to the rapid evaporation of the etchant. Processing is possible even at a temperature of 5 ° C. or lower, but it is not practical when the etching rate is extremely low.

Etching may be performed while applying ultrasonic waves to the etching solution as necessary. The etching rate can be increased and a liquid stirring effect can be expected.

When the altered portion is formed so as to be exposed only on the upper surface side (laser pulse incident side) of the glass plate, a hole can be formed only on the upper surface side of the glass plate by etching. Conversely, when the altered portion is formed so as to be exposed only on the lower surface side of the glass plate (opposite to the laser pulse incident side), holes can be formed only on the lower surface side of the glass plate by etching. Further, when the altered portion is formed so as to be exposed on the upper surface side and the lower surface side of the glass plate, the through hole can be formed by performing etching. In addition, a film for preventing etching may be formed on the upper surface side or the lower surface side of the glass plate, and etching may be performed only from one side. Etching may be performed after forming an altered portion that is not exposed on the surface of the glass plate and then polishing the glass plate so that the altered portion is exposed. By changing the formation conditions and etching conditions of the altered part, cylindrical through-holes, hourglass-shaped through-holes, frustoconical through-holes, conical holes, frustoconical holes, cylindrical It is possible to form holes of various shapes such as holes.

It is also possible to form a groove by forming a plurality of holes so that they are continuous. In this case, a plurality of altered portions arranged in a line are formed by irradiating a plurality of laser pulses so as to be arranged in a line. Thereafter, a groove is formed by etching the altered portion. Irradiation positions of a plurality of laser pulses do not have to overlap, and holes formed by etching only need to connect adjacent holes.

FIG. 1 shows a schematic diagram of one embodiment of the production method of the present invention. As shown in FIG. 1A, the altered portion 13 is formed so as to penetrate the glass plate 12 by irradiation with the laser pulse 11. Next, the through hole 14 is formed by etching from both surfaces of the glass plate 12. In FIG. 1B, the through hole 14 has a shape that connects two frustum-shaped holes.

As described above, the hole formed by the method of the present invention may be a bottomed hole or a through hole.

Also, when removing the altered portion by etching in the step [ii], for example, a groove whose width periodically changes can be obtained by stopping the etching when a part of the hole is connected. The change in the width does not need to be periodic, and it is only necessary that a portion having a narrow width is formed depending on the interval at which the altered portion is formed. Thus, according to this invention, the glass plate which has a location where a groove | channel has a partially narrow width | variety can be obtained. This groove has a narrow portion (location) when viewed from a direction perpendicular to the surface of the etched glass plate. This relatively narrow portion connects the relatively wide portions. The relatively wide portion is a portion generated by etching a plurality of altered portions by laser pulse irradiation.

The present invention includes embodiments in which the above configurations are combined in various ways within the technical scope of the present invention as long as the effects of the present invention are exhibited.

EXAMPLES Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples at all, and many variations are within the technical idea of the present invention. This is possible by those with ordinary knowledge.

Hereinafter, examples based on various compositions of the glass substrate subjected to drilling are described together with the quality evaluation of the holes. The quality evaluation of the holes is based on the following criteria. All the evaluations were conducted after laser irradiation and inspection and evaluation after completion of the drilling by etching. “◯” is practically acceptable level and “×” is unacceptable level.

(1) Circularity or contour With respect to the opening of a substantially circular hole formed on the glass substrate (on the surface), the ratio of the length of the long side to the short side (long side / short side) is 1.5. The following were marked with ○, and the others were marked with ×. This is because when a glass substrate having a so-called flat opening hole is used for an electronic circuit board, the pitch varies, which is not preferable. An example is shown in FIG. FIG. 2A shows the ◯ level, and FIG. 2B shows the X level.

(2) Smoothness of the inner wall of the hole When the cross section of the hole observed when cut in parallel with the thickness direction of the glass substrate is examined with an optical microscope of 100 times or more, the inner wall of the hole has no visible irregularities. ○. When used for an electronic substrate interposer, if there are irregularities, it is a necessary characteristic because the high frequency characteristics deteriorate. An example is shown in FIG. FIG. 3A shows the ◯ level, and FIG. 3B shows the X level.
Furthermore, evaluation was not possible = “−” for the case in which a substantially circular outline-like object was formed on the glass surface and the hole depth did not reach 0.05 mm.

(3) Penetration Since whether or not to penetrate depends on the thickness of the glass substrate, it is not an indispensable effect of the invention. The case where it penetrated was defined as “through hole”, and the case where it did not was defined as “bottomed hole”. If a hole having a depth approximately equal to the opening diameter of the hole was formed, it was defined as a “bottomed hole”. An example is shown in FIG. 4A is a “penetrating” state, and FIG. 4B is a “bottomed” state. In other cases, the evaluation was not possible = “−”.

What can be used as glass for electronic substrates can be evaluated as “◯” for (1) and (2).

Furthermore, the thermal expansion coefficient and the absorption coefficient α were evaluated by the following methods.

(4) Thermal expansion coefficient The average thermal expansion coefficient at 50 to 350 ° C. is measured as follows. First, a cylindrical glass sample having a diameter of 5 mm and a height of 18 mm is prepared. This is heated from 25 ° C. to the yield point of the glass sample, and the thermal expansion coefficient is calculated by measuring the elongation of the glass sample at each temperature. An average value of thermal expansion coefficients in the range of 50 to 350 ° C. can be calculated to obtain an average thermal expansion coefficient. The measurement was performed using a thermomechanical analyzer TMA4000SA manufactured by NETZSCH under the temperature increase rate condition of 5 ° C./min.

(5) Absorption coefficient α
The absorption coefficient α is calculated by measuring the transmittance and reflectance of a glass substrate having a thickness t (cm). For a glass substrate having a thickness of t (cm), a transmittance T (%) at a predetermined wavelength (wavelength of 535 nm or less) and a reflectance R (%) at an incident angle of 12 ° are measured with a spectrophotometer (UV manufactured by JASCO Corporation). Measurement is performed using a visible near-red spectrophotometer V-670). The absorption coefficient α is calculated from the obtained measured value using the following formula.
α = (1 / t) * ln {(1-R) / T}

<Examples 1-22 and Comparative Examples 1-2>
[Glass melting and molding]
A predetermined amount of glass raw material powder was prepared so that about 300 g of glass was obtained with the composition shown in Tables 1 to 3 below, and a glass block having a certain volume was prepared by a normal melting and quenching method using a platinum crucible. . In the middle, the mixture was stirred for the purpose of improving the glass uniformity or clarifying.

The melting temperature and time were set to suit the melting characteristics of each glass. For example, in the case of Example 1, it was melted at about 1600 ° C. for 6 hours, poured out on a carbon plate and molded. In order to relieve the residual stress inside the glass, 550 ° C. to 700 ° C., which is a temperature range near the annealing point, was passed over about 4 hours, and then naturally cooled to room temperature.

From the glass block thus molded, a thin glass substrate having a thickness of about 0.1 to 1.5 mm was cut out to obtain a sample for forming an altered portion.

[Formation of altered part]
For laser processing, a high repetition solid-state pulsed UV laser manufactured by Coherent, Inc .: AVIA355-4500 was used. This is a third harmonic Nd: YVO ₄ laser, and a maximum laser power of about 6 W can be obtained when the repetition frequency is 25 kHz. The dominant wavelength of the third harmonic is 355 nm.

A laser pulse (pulse width 9 ns, power 0.8 W, beam diameter 3.5 mm) emitted from the laser device is expanded four times with a beam expander, and this expanded beam is adjusted within a range of 5 to 15 mm in diameter. The optical axis was adjusted with a galvano mirror, and it was condensed inside the glass plate with an fθ lens having a focal length of 100 mm. By changing the iris size, the laser diameter was changed to vary the NA from 0.020 to 0.075. At this time, the laser beam was condensed at a position separated by 0.15 mm in physical length from the upper surface of the glass plate. The laser beam was scanned at a speed of 400 mm / s so that the irradiation pulses did not overlap.

After the laser light irradiation, it was confirmed with an optical microscope that a modified portion different from the other portions was formed in the portions irradiated with the laser light in the glass of each example. Although there is a difference for each glass, the altered portion is generally formed in a columnar shape and reaches from the vicinity of the upper surface of the glass to the vicinity of the lower surface.

The sample was irradiated with laser at a repetition frequency of 10-25 kHz. Moreover, the position (upper surface side or lower surface side) of the altered portion formed on the glass was optimally adjusted by changing the focal position in the thickness direction of the glass.

Further, in order to attempt processing on a plurality of laser processing glasses having different compositions, the laser condensing position was adjusted for each glass of the example, and processing was performed under conditions that seemed optimal. In order to grasp the difference between the glasses, a glass substrate having a uniform thickness of 0.3 mm was used except for Examples 16 to 20. In addition, processing was attempted using a glass substrate of about 0.1 to 1.5 mm in order to grasp the glass thickness dependency.

[etching]
Etching was performed by immersing the sample after laser irradiation in an etching solution bath while stirring an etching solution in which 2.13 wt% HF (original concentration: 4.5%) and 3.28 wt% HNO ₃ were mixed. Although the etching time depends on the plate thickness, the liquid temperature was set to 33 ° C. for 90 to 120 minutes.

Each glass obtained was evaluated by the above method. The evaluation results are shown in Tables 4-6.

As shown in Examples 1 to 5, the glass according to the present invention has absorption coefficients α of 11.2, 5.6, 2.1, 20.0, 34.1 / cm in order, A favorable hole drilling could be realized in the presence of pure CuO. As shown in Tables 1 to 3, with the exception of Example 22, the glasses of Examples 1 to 21 are all alkali-free glass.

The glass substrate after etching has a thickness of several tens of microns thinner than that before etching in any of the embodiments, and a hole with a diameter of about 50 to 100 μm and a depth of about 0.15 to 0.3 mm is formed. I was able to confirm. In particular, in Examples 5 and 20, holes that were not penetrated but were clean on the surface were confirmed.

From the above results, the glass for laser processing according to the present invention can make a hole having a circular outline and a smooth inner wall in a micro-hole batch processing technique that combines the formation of an altered portion by ultraviolet laser irradiation and etching. It could be confirmed.

The glass for laser processing of the present invention can be suitably used as a glass substrate for interposer, a glass substrate for mounting electronic components, and further a glass substrate for mounting optical elements after drilling. An interposer is a board that relays boards having different distances between terminals such as an IC and a printed board having different wiring design rules.

The glass substrate for an interposer obtained from the laser processing glass of the present invention has good matching with the Si substrate that may be used in combination in terms of thermal expansion coefficient, and further contains no or very little alkali metal component. For this reason, the electrical characteristics also have very effective characteristics such as no deterioration in the high frequency range. In addition, the glass substrate for interposers obtained from the laser processing glass of the present invention is also characterized by being optically transparent from the visible light region to the near infrared region, unlike the Si substrate. For this reason, light can be extracted from the photoelectric conversion element mounted on the substrate through the substrate, and conversely, the light can be incident through the substrate, so that a mixed substrate of optical elements and electric circuits can be easily manufactured. .

FIG. 5 shows a schematic example of the glass substrate 23 for an interposer obtained from the laser processing glass of the present invention. This figure shows an example of an interposer used for bonding a light emitting / receiving element 21 such as an IC having a different design rule such as a wiring pitch and a printed wiring board.

A circuit pattern 22 or electrode patterned by combining electroless plating and electrolytic plating on a single side or both sides of the laser processing glass of the present invention that has been perforated. 24 is formed. The material of the circuit and electrodes is not particularly limited, but Au, Cu and the like are preferable because they have low resistance and good high frequency characteristics.

When forming these circuit patterns, Au or Cu may be filled in through holes at predetermined positions. The front and back conductivity can be ensured. These can be filled at the same time during plating, but can also be prepared by a known method before and after the plating step.

After that, it suffices to mount a desired electrical component or light emitting / receiving element, and it can be easily mounted on a desired circuit board.

The laser processing glass of the present invention is useful for the production of glass with a hole having a circular contour and a smooth inner wall.

Claims (13)

1. The glass composition is expressed in mol%,
   45.0% ≦ SiO ₂ ≦ 70.0%,
   2.0% ≦ B ₂ O ₃ ≦ 20.0%,
   3.0% ≦ Al ₂ O ₃ ≦ 20.0%,
   0.1% ≦ CuO ≦ 2.0%,
   0% ≦ TiO ₂ ≦ 15.0%, and 0% ≦ ZnO ≦ 9.0%,
   And 0 ≦ Li ₂ O + Na ₂ O + K ₂ O <2.0%
   This is a glass for laser processing.
2. The glass for laser processing according to claim 1, wherein 55.0% ≦ SiO ₂ + B ₂ O ₃ ≦ 80.0%.
3. The laser processing glass according to claim 1, wherein 6.0% ≦ MgO + CaO + SrO + BaO ≦ 25.0%.
4. The glass for laser processing according to any one of claims 1 to 3, wherein 5.0 ≦ Al ₂ O ₃ /CuO≦60.0.
5. 5. The method according to claim 1, further comprising, as a coloring component, an oxide of at least one metal selected from the group consisting of Fe, Ce, Bi, W, Mo, Co, Mn, Cr, and V. The glass for laser processing as described.
6. The glass composition is expressed in mol%,
   45.0% ≦ SiO ₂ ≦ 68.0%,
   2.0% ≦ B ₂ O ₃ ≦ 20.0%,
   3.0% ≦ Al ₂ O ₃ ≦ 20.0%, and 0.1% ≦ CuO ≦ 2.0%,
   Substantially free of TiO ₂ and ZnO and 58.0% ≦ SiO ₂ + B ₂ O ₃ ≦ 80.0%,
   8.0% ≦ MgO + CaO + SrO + BaO ≦ 20.0%,
   0 ≦ Li ₂ O + Na ₂ O + K ₂ O <2.0%,
   6.0 ≦ Al ₂ O ₃ /CuO≦60.0
   The laser processing glass according to any one of claims 1 to 5, wherein:
7. The glass composition is expressed in mol%,
   50.0% ≦ SiO ₂ ≦ 68.0%,
   6.0% ≦ B ₂ O ₃ ≦ 18.0%,
   7.0% ≦ Al ₂ O ₃ ≦ 18.0%,
   0.1% ≦ CuO ≦ 1.8% and 1.0% ≦ TiO ₂ ≦ 10.0%,
   Substantially free of ZnO and 58.0% ≦ SiO ₂ + B ₂ O ₃ ≦ 80.0%,
   8.0% ≦ MgO + CaO + SrO + BaO ≦ 20.0%,
   0 ≦ Li ₂ O + Na ₂ O + K ₂ O <2.0%,
   6.0 ≦ Al ₂ O ₃ /CuO≦60.0,
   0 ≦ TiO ₂ /CuO≦20.0
   The laser processing glass according to any one of claims 1 to 5, wherein:
8. The glass composition is expressed in mol%,
   50.0% ≦ SiO ₂ ≦ 68.0%,
   6.0% ≦ B ₂ O ₃ ≦ 18.0%,
   7.0% ≦ Al ₂ O ₃ ≦ 18.0%,
   0.1% ≦ CuO ≦ 1.8%, and 1.0% ≦ ZnO ≦ 9.0%,
   Substantially free of TiO ₂ and 58.0% ≦ SiO ₂ + B ₂ O ₃ ≦ 80.0%,
   8.0% ≦ MgO + CaO + SrO + BaO ≦ 20.0%,
   0 ≦ Li ₂ O + Na ₂ O + K ₂ O <2.0%,
   6.0 ≦ Al ₂ O ₃ /CuO≦60.0
   The laser processing glass according to any one of claims 1 to 5, wherein:
9. Furthermore, the glass composition is expressed in mol%,
   2.0% ≦ MgO ≦ 10.0%,
   1.0% ≦ CaO ≦ 10.0%,
   The glass for laser processing according to any one of claims 1 to 8, which contains 1.0% ≤SrO≤10.0% and 0≤BaO≤6.0%.
10. Furthermore, the glass composition is expressed in mol%,
    3.0% ≦ MgO ≦ 8.5%,
    2.0% ≦ CaO ≦ 6.5%,
    The glass for laser processing according to any one of claims 1 to 8, comprising 2.0% ≦ SrO ≦ 6.5% and 0 ≦ BaO ≦ 6.0%.
11. The glass for laser processing according to any one of claims 1 to 10, which has a thermal expansion coefficient of 60 × 10 ^-7 / ° C or less.
12. The glass for laser processing according to any one of claims 1 to 11, wherein the absorption coefficient α is 2 to 40 / cm.
13. A step [i] of forming a modified portion in the irradiated portion by condensing and irradiating the laser processing glass according to any one of claims 1 to 12 with a laser pulse by a lens;
    And a step [ii] of forming a hole in the laser processing glass by etching at least the altered portion using an etching solution.

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